I believe Craig Bodington did a write up on that caliber?  Either an STW or RUM cartiridge necked down to a 25.  You'll get 4000 fps and shoots out to 500 with very little drop.  Obviously for such performance you'll be giving up something...barrel life.  Should be fun to shoot and a good gun for you varminters out in the midwest.   The only problem is if you can only run 1000 rounds through it.  I'd be screwed after a few weeks, b/c I'd be pumping a lot of rounds through that one.
It would be nice not to worry about ranging and dialing a scope in, though.  Just put the crosshairs on it and pull the trigger.  Throw in another $500-$600 and have him make you up another barrel, ready to put on for next year